Google was accused Wednesday of effectively removing from the Internet a Web site that is critical of the Church of Scientology after it deleted links to some of the site's pages from its search engine.

The popular search company said it removed the links after it received a copyright-infringement complaint from the Church of Scientology. Andreas Heldal-Lund, Webmaster of the site Xenu.net, said in a Usenet posting that the complaint demanded that Google take down a large number of references to different parts of Xenu.net.

"The complaint mentions a ridiculous list of addresses, which successfully removes the whole site from their engine," he said.

Search engines routinely remove links to URLs, or Web addresses, upon request to avoid litigation. Under the Digital Millennium Copyright Act (DMCA), sites cannot be held liable for copyright infringement provided they promptly take down content flagged by a copyright holder. Much of that activity has targeted links to MP3 files that turn up on search engines.

Digital rights advocates said the Church of Scientology's takedown request is noteworthy because it underscores potential conflicts between the DMCA and free speech.

"The danger is that people will attempt to silence critics under the guise of copyright infringement," said Fred von Lohmann, an attorney with San Francisco's Electronic Frontier Foundation.

In the Xenu.net case, the removed links led to pages that contain material copyrighted by the Church of Scientology. On his site, Heldal-Lund defends this use of copyrighted material, saying that he believes Scientology survives "through the protection afforded it by copyright laws in a way that copyright laws were not designed to address."

A representative for the Church of Scientology could not be immediately reached for comment.

The right to link has been the subject of several high-profile lawsuits, including a dispute between hacker publication 2600.com and the motion picture industry over code known as DeCSS that can theoretically be used to crack DVDs. In that case, a federal judge in New York held that links to the DeCSS code violated the anti-circumvention clause of the DMCA, which bars trafficking in software that can be used to defeat copy protection. That decision was upheld on appeal.

Another linking case under way in New York involves MP3 search service MP3Board.com, which is challenging the DMCA's notice and takedown provision. The case, filed in May 2000, is pending. MP3Board had created a delisting feature allowing copyright holders to pull offending links automatically, but the move did not mollify copyright holders, who were upset that the search engine included results from peer-to-peer exchanges such as Gnutella.

The EFF's von Lohmann said search engines are not required to comply with takedown notices, but that most do to avoid the risks of litigation.

"Search engines can't take on every copyright holder," he said. "It's hard to say search engines should pay for this fight themselves."

Google noted that Xenu.net has some recourse. "Google provides Webmasters the ability to have their content reinstated if they submit a counter notification to Google," the company said in a statement.

Xenu.net's Heldal-Lund said this would require the services of a lawyer and would be prohibitively expensive.